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Building Principles: Magic From the Tap
Most children are fascinated by magicians. I remember being certain that a magic wand, would indeed, produce whatever I wanted. As you get older though, you come to realize that behind the "magic" is much preparation and careful planning to create an illusion of something out of nothing. It's funny, but though most adults recognize the "tricks" behind a stage magic show, they still regard safe, potable water as magic. You know, turn the faucet and Shazam! Water springs forth! But you know differently. The water doesn't bring itself out of the ground nor does it materialize at the tap without help. And moreover, you know that without proper care and careful monitoring, what comes from the faucet can be more harmful than helpful. By now, you should be well on your way to opening camp for the season. One of the most time- and labor-intensive exercises is getting the water system on line. In this column, we're going to look at some of the important, not-to-be-missed details of seasonal startup of the water system.
Well, Well, Well. What Do We Have Here?
If camp uses wells to supply water, this is the very best place to begin. Start by looking around the pipe that sticks up out of the ground, called the "well head." Like an open wound of the surface, this is the most vulnerable spot for contamination to enter your well and aquifer. You need to go to extraordinary efforts to protect it and the ground around it by ensuring that the well head extends at least 12"–18" above the surrounding earth. If it's surrounded by a manhole or other structure, ensure that it drains freely and doesn't hold water. If it's in a pit or vault, and you've had to install a sump pump because it stays wet, maybe this is the year to extend everything above ground. That way, there are no confined space issues (OSHA regulations apply here!) discouraging your staff from attentive operation of the system, and you'll have much less likelihood of source contamination. Concrete around the well head should be solid, and without cracks that would allow water to seep alongside the well casing. If the well head simply sticks out of the ground, look at how surface water flows nearby. Regrading around the well head to divert surface flow is a fast, cheap, and easy method to help reduce surface water infiltration.
Regardless of whether you can see sources of surface water infiltrating into the well, there may be bacteria that's been growing in the well since you "turned off the lights" last fall. Your best pre-emptive bet is to sanitize the well before you do anything else. This can be a little tricky because most commercially available systems require that you know how much water is in the well when you start. Specifically, that's the amount of water in the well hole from the top of the water surface to the intake of the well pump, and figuring out those numbers can be tricky too. A simple method is to drop a small pebble into the well casing and listen for the "plop" while marking time with a watch. Put the count into this formula:
Distance in feet = (number of seconds) * (number of seconds) * 16.1
Now you know how far down the water surface is. If you don't have it written in the well cap, go to your files and find the invoice from the last time you replaced the well pump. It will list the "pump setting" which is the depth to the top of the pump. To figure out how deep the water is, take the difference between the two:
Depth of water in the well = pump setting – depth to the water level
Finally, assume that the well hole is circular and matches the size of the casing at the well head. This isn't always true, but it's close enough for what we're doing. Measure its diameter in inches. The amount of water in the well is calculated like this:
Volume of water (in gallons) = (5.87) * (diameter/12) * (diameter/12) * (depth of water)
One state uses the following procedure for disinfection. Your state or region's procedures may differ, so you should contact that agency for specific instructions. But it's a pretty solid "how to." To disinfect the well over a twentyfour- hour period, you'll need 3 pints of household chlorine bleach for each 100 gallons of water. For example, if you calculate that you'll have 525 gallons of water in the well, you'll need (525/100) * 3 or about 15 pints of bleach, or just about 1 gallon of bleach. For best results and to reduce the corrosivity of the chemical splashing on stuff on the way down the hole, dilute the bleach 50/50 with water. Now, mix the stuff in the well. Connect a garden hose to the raw water sampling tap, run it back into the well head, and turn on the well pump.
There's likely to be a lot of pressure, so make sure that the hose is secured and not able to squirt out. Let that run for an hour or so, and then shut off the well pump. Put the cap back on the well, and let things sit for at least twenty-four hours. The highly chlorinated water you've made will be very useful when you disinfect the rest of the system, so don't kill the grass and the critters in the local creek by emptying it on the ground. There is one important exception: If you've been told that you have "iron bacteria" in your well, the shocking procedure is likely to generate a pretty good slug of chunky, slimy goo laden with active bacteria colonies (the chlorine only kills the ones on the outside of the mass). This is massive colonies of bad stuff that you really, really don't want in the rest of your system (even though it's probably already there to some extent). In this case, flush the chlorinated water to an open area like a parking lot where sun and air will drive the chlorine out of the solution before it hits the ditch, creek, or stream. If you want to see some really nasty stuff, Google images of "iron bacteria."
A Bacterial Killing Spree!
It's likely that your water works are pretty simple. There will be some amount of storage, a method of providing pressure, and disinfection equipment. You may also have other treatment systems like filtration, softening, or aeration. We're going to save those pieces for another time because the most critical element is the disinfection equipment. Usually, this is camp's only line of defense against water-borne illness.
The simplest disinfection systems use a small pump that draws a concentrated chlorine solution from a crock or tank. Usually, it is plugged into an outlet that is on the same circuit as the well pump, so that when the well pump is running and delivering water, the chlorine pump is pushing disinfectant into the system at the same time. Turbulence in the pipe mixes the water and the chlorine. Called "peristaltic" or "metering" pumps, these can have many extra accessories, but two adjustment knobs are really all that you need to manage the dosing. The frequency adjustment varies the rate at which the piston moves back and forth. The stroke adjustment varies the distance that the piston moves between drawing up and injecting disinfectant. You should work to keep both of these settings as close to their center of operation range as possible. By design, these are the most efficient settings for the pump.
There are also some important things to check before you start them. The first and most important thing to do is to READ THE INSTRUCTIONS. If you don't have any, you can go online and find them. Do not assume that you know what there is to know simply because you've been doing this or that for years. The most common mistakes and causes for malfunction are completely avoidable by simply humbling yourself before the humble instruction booklet.
One of the most common mistakes involves the intake tubing. Pumps often come with five or six feet of polyethylene tube with a ball valve on the bottom. You will always find in the instructions that in order for the pump to draw liquid reliably, the ball valve needs to work. For that to happen, it must hang freely, straight down, in the solution tank. Many inattentive operators will simply coil the excess tube in the bottom of the tank. WRONG! For the system to work correctly, measure the length carefully from the ball valve end, and cut the pump connection end of the tube. If it's curled, attach a weight to the bottom and hang it in the sunshine to allow the heat of the sun to soften it while it straightens.
More trouble-in-the-making comes from not having prepared for the pump to die without notice. The smartest approach is to have an identical chemical feed pump on the shelf right next to the working unit. Notice that I said an "identical" feed pump. Why? There are several great reasons. First and probably the most important is because you're familiar with that particular model and its operating characteristics. You know that all of the fittings and accessories will fit and that swapping pumps will be quick and straightforward, which is what you need in a water crisis. Moreover, if one dies from something really catastrophic like a lightning strike, you'll be able to salvage useful parts (like valves and sometimes seals) before you throw the unit hulk in the garbage.
If you decide to not invest in another pump, the least that you should do is buy a rebuild kit and install it before each season begins. This is particularly important for seasonal operations where the seals dry out during the six to nine Building Principles continued from page 12 months that the pump isn't working. My favorite mail-order supply house and great friend to camps nationwide, USA Bluebook (www.usabluebook.com) carries an enormous array of chemical feed pumps and repair parts for the largest and most reliable manufacturers. They have a super knowledgeable staff who can help you make sure that you get exactly what you need on the first try, because again, the middle of a water crisis is no time for guessing and hoping. Be certain to tell the technician what chemical you're handling with the pump, because the internals of the equipment have to be matched to the properties of the chemical. Identically appearing chemical feed pumps may be configured to convey very different solutions and will probably not perform as well or as long if misused.
There's Strength in Numbers
What about the chemical itself? You may not know that the chlorine solution in the feed tank will become weaker over time. Heat (like in an enclosed shed) and direct sunlight both can really hasten that weakening. And if the chemical you're injecting is weaker in August than it was in June, you'll probably need to increase the injection rate to compensate for that change, right? But how do you know what the chlorine concentration is in the tank, especially if you're adding water or concentrate over time? The answer is a piece of equipment called a "hydrometer." While they actually measure the specific gravity of the fluid, a simple chart allows you to convert the specific gravity to chlorine content. So for less than $150, you can know for certain how to adjust the feed rate to match the concentration in the feed tank.
Spreading the Wealth
Well, now you've disinfected the well and your chemical feed pump is ready to rock. The next step is to disinfect the water distribution system all the way to each tap. Remember that we have a pretty strong disinfectant solution stored in the well (provided it hasn't been more than a few days since you disinfected it). You should also have a fresh, full crock of hypochlorite solution. Make sure that all faucets and taps are closed in the distribution system. Start the well pump to fill the system, and beginning with the most remote tap, open first a hot water tap (to fill the hot water heater) and leave it open until you smell chlorine. Then open the cold water tap again until you smell chlorine. Using a chlorine test kit or strip, you should read 50–200 parts per million in the water. (Confirm the regionally required chlorine residual with your regulating health department or environmental protection agency.) Proceed upstream toward the well, checking chlorine content at each new building to ensure that the chlorine content is adequate.
Different agencies have different requirements that relate the chlorine concentration with the amount of contact time necessary to ensure disinfection. Moreover, there is often a requirement to check chlorine content at the end of the period as well, and if it's fallen below a certain level, the procedure must be repeated. A sharp drop in the chlorine content during the contact time may indicate very dirty, cloudy, or bacteria-laden water, so this step should never be disregarded.
Finally, you should understand that the water supply at your camp is subject to federal regulation under the Safe Drinking Water Act (SDWA). It's known as a "transient, non-community water supply." The simple procedures that we've discussed here apply to you, all the time that the system is in service. The permit issuing authority MUST be notified of even a momentary loss of confidence in the disinfecting system or in the pressurizing system. Among other things, that includes the failure of a chlorine pump, the crock runs dry, the well pump is replaced, or if a water line breaks.
There are few things at camp which are more critical than a clean, safe water supply, and few that are as vulnerable to spreading summer camp-ending disease. Get summer off to the best possible start. Make sure that you and your water system and supply are ready to serve reliably and safely all summer long!
Rick Stryker is a professional engineer with a passion for helping camps solve their infrastructure issues through careful planning, crisis management, and education. He can be reached at 570-828-4004 or by e-mail at email@example.com.
Originally published in the 2010 May/June issue of Camping Magazine.